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Why are subwoofers so.. "not universal in crossover freq. dials"?

AJM1981

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I have owned subwoofers and although there might be differences, if there is any type of general loudspeaker that comes close to having a label of being kind of interchangeable in the right room conditions without having that much of a "preferred signature", it's a subwoofer.

Now, they are pretty universal when it comes to connections. But what I don't understand is that most of them have a dial with a quite high crossover point which seems to change from type to type, with no logic in pricepoint to bottom crossover freq. whatsoever.

I know there are DSP solutions to cap them at a preferred crossover point, but sometimes it requires extra gear because not all amps support this (I have owned an Arylic A50+ in which I could cap it with its extra software, but now I have a setup that doesn't).

Questions?
- Why is it possible that for example B&W has a quite well priced and decent versatile smaller factor form sub (ASW608 - I own this one) with a dial goes as low as 32hz, but any bigger box by competitors starts at 40 or 60 hz ?
- Why can't they all adopt a 32hz bottom position as the standard? since most subs really have that potential. This way it connects well to the most common types of bookshelf systems and their roll-off and even 3-way systems. It would only leave the floorstanders out, but that seems fine.

Just curious.
 
Why can't they all adopt a 32hz bottom position as the standard? This way it connects well to the most common types of bookshelf systems and their roll-off and even 3-way systems. It would only leave the floorstanders out, but that seems fine.
Actually, a crossover frequency of 32Hz would only work well with some floorstanders which can play down to 30Hz.

For the majority of bookshelf speakers, you'd be left with a hole in the response as the mains would roll off way before the sub takes over.

That's also the reason why having a crossover that goes so low is kind of a niche feature, especially on SFF subs.

If you already have beefy floorstanders that play down to 30Hz, then you're less likely to try to augment them with a sub, doubly so with a small sub.
 
Actually, a crossover frequency of 32Hz would only work well with some floorstanders which can play down to 30Hz.

For the majority of bookshelf speakers, you'd be left with a hole in the response as the mains would roll off way before the sub takes over.

That's also the reason why having a crossover that goes so low is kind of a niche feature, especially on SFF subs.

If you already have beefy floorstanders that play down to 30Hz, then you're less likely to try to augment them with a sub, doubly so with a small sub.
Thanks for the reply, I made a bit of a mistake with the focus on the bottom 32hz instead of the range of the dial starting from there.

For example. I own the Wharfedale Denton 85th model, a larger type of bookshelf loudspeaker. Its crossover frequency according to specs is 40 hz because that seems to be the roll off point.

But trying a sub with the bottom dial option at 40hz didnt really work. I often had the idea it still kind of "doubled" a bit at that range. Maybe due to the bass ports and the wall the loudspeaker was close to and the room.

I managed to get the sub to 38hz or 39 hz using DSP. There 'was' a minor gap there, but it gave the impression of connecting better without any minor "overdubbing".
 
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When there is no system for precise control of the crossover filters, having an internal crossover of the sub as low as possible can really make the difference.
In the bedroom I have Elac unifi ub52s which have major limitations in going low, and already at 60hz they have a very attenuated response. Despite this I had to set the sub's crossover to 40hz to have a smooth enough response without any sense of overlapping bass bloat (which I hate)
 
You can't have a standard crossover range because 1) the filters used might be different, although I think most of them are 2nd-order and 2) the speakers themselves will have different frequency responses and extensions.

Realistically, trying to integrate a sub with just a crossover (and not PEQ) is like trying to sew with a screwdriver. Even if you get the crossover exactly right based on anechoic responses, your in-room response will still be dominated by the room.

I'm an advocate of crossing fairly high and using PEQ - I actually run my sub almost up to 200hz. The reason being it's easier to fill nulls at any given frequency when you have more sources for that frequency.
 
When there is no system for precise control of the crossover filters, having an internal crossover of the sub as low as possible can really make the difference.
In the bedroom I have Elac unifi ub52s which have major limitations in going low, and already at 60hz they have a very attenuated response. Despite this I had to set the sub's crossover to 40hz to have a smooth enough response without any sense of overlapping bass bloat (which I hate)
Most loudspeakers are (unsurprisingly), well made for the frequency range in most common types of music.

So I really don't miss bass in that sense. But to have a slight bit of that pulse presence at the bottom frequencies of some music and films is the thing. Gaps are fine for me there.

You can't have a standard crossover range because 1) the filters used might be different, although I think most of them are 2nd-order and 2) the speakers themselves will have different frequency responses and extensions.

Realistically, trying to integrate a sub with just a crossover (and not PEQ) is like trying to sew with a screwdriver. Even if you get the crossover exactly right based on anechoic responses, your in-room response will still be dominated by the room.

I'm an advocate of crossing fairly high and using PEQ - I actually run my sub almost up to 200hz. The reason being it's easier to fill nulls at any given frequency when you have more sources for that frequency.
What equipment and software do you use to achieve this? When I still got my Arylic A50+ amp, I could go in quite some tweaks with its workbench software. Later on I switched to a classic Sansui integrated amp and an Arylic pre amplifier (to which the sub is connected) Unfortunately the workbench software is not supported on the pre-amp.

I just use it in a bedroom by the way, it is not for a home theatre system.
 
What equipment and software do you use to achieve this?
I personally use this

https://www.audiophonics.fr/en/dsp-...sigmadsp-2556bit-4-to-8-channels-p-13043.html

It has no digital inputs and is not balanced, furthermore it has not been reviewed here so I don't know what the measured performances are, however it has enormous versatility being able to manage four inputs and eight outputs, mixing and creating crossover filters for each output, as well as 10 peq and latency management. It also has intuitive and easy-to-use software to manage everything with.
I use it to manage three subwoofers and I am satisfied with it
 
What equipment and software do you use to achieve this?
I just use EQAPO on Windows... although right now it's just for my office setup, I also had it going in the living room.

You can get a windows Mini-PC for about $100. Add any DAC or adapter that has SPDIF in. Send the audio in there, then out to any DAC of your choice.

Congratulations, you now have unlimited bands of EQ. :)

Take your measurements in REW and develop a correction curve, then you can load that directly in EQAPO. Congratulations, your bass is fixed. :)

Lots of other people use MiniDSP units, others Raspberry Pi, and you can even buy DSP modules with SPDIF in/out on AliExpress, which is what I plan to try next.
 
Why would minimal frequency be under 60 Hz as from there it's one long wave?
I don't know speakers that would not benefit of getting that range of their neck. Good 8" woofer driver goes down to 80 Hz on it's own 0 dB and two will only go to where one goes - 3 if it reaches 60 Hz together it will extend to - 6 dB. Really the hole point of subwoofer isn't only low end extension but also getting a significant heavy load out of the mains and you do it on woofer highest point in order to lower the THD on it and extend that beyond bass range to mids and lower highs (beyond 1 KHz) where our hearing is most sensitive. Of course impact is higher on two ways compared to three ways where mid driver is already physically separated (for a same reason). Now take into consideration how transition frequency for psy acoustical bass perception is 100~105 Hz and that you don't want woffer to wonk or ring above that and you come to requirement for two sub's in 2.2 setup (each sub per one main and under it or close to it) and high crossover point at 120~130 Hz. If you want very good crossover it needs a work towards it in transition range and towards mathematical model and that's for each and any crossover for given drivers along with box and room influences. Not either easy or cheap thing to do any way you look at it or do it. Sometimes you even use more capable one to complement and correct shortcomings of less capable one and so on.
 
Why would minimal frequency be under 60 Hz as from there it's one long wave?
I don't know speakers that would not benefit of getting that range of their neck. Good 8" woofer driver goes down to 80 Hz on it's own 0 dB and two will only go to where one goes - 3 if it reaches 60 Hz together it will extend to - 6 dB. Really the hole point of subwoofer isn't only low end extension but also getting a significant heavy load out of the mains and you do it on woofer highest point in order to lower the THD on it and extend that beyond bass range to mids and lower highs (beyond 1 KHz) where our hearing is most sensitive. Of course impact is higher on two ways compared to three ways where mid driver is already physically separated (for a same reason). Now take into consideration how transition frequency for psy acoustical bass perception is 100~105 Hz and that you don't want woffer to wonk or ring above that and you come to requirement for two sub's in 2.2 setup (each sub per one main and under it or close to it) and high crossover point at 120~130 Hz. If you want very good crossover it needs a work towards it in transition range and towards mathematical model and that's for each and any crossover for given drivers along with box and room influences. Not either easy or cheap thing to do any way you look at it or do it. Sometimes you even use more capable one to complement and correct shortcomings of less capable one and so on.
For me personally it counts that there is an option to dial in a range from below 40 to 32 hz.

For the manufacturer I understand a top dial option in the upper bass regions. As there are probably people who use true satellite speakers. Those tiny cubes on a stick.

I tried it once for fun with the sound of our simple lcd TV in the bedroom that has no bass in its sound at all. Turned on the tv sound and the sub to its max position and disabled the loudspeakers. It wasn’t great, but interestingly acceptable in some sense :)

I just use EQAPO on Windows... although right now it's just for my office setup, I also had it going in the living room.

You can get a windows Mini-PC for about $100. Add any DAC or adapter that has SPDIF in. Send the audio in there, then out to any DAC of your choice.

Congratulations, you now have unlimited bands of EQ. :)

Take your measurements in REW and develop a correction curve, then you can load that directly in EQAPO. Congratulations, your bass is fixed. :)

Lots of other people use MiniDSP units, others Raspberry Pi, and you can even buy DSP modules with SPDIF in/out on AliExpress, which is what I plan to try next.
Thanks for the contribution. I would probably go into this all when having more than 2.1 to calibrate and use this post as a reference. Since I only use a stereo and sub I search for the simplest of solutions without extra components and wires. With the workbench software of approx 20 euro’s for my previous Arylic a50 in the bedroom it was kind of there already having a Polk sub that could be just capped at amp level to under 40hz.
 
@AJM1981 I don't think a 8" woofer speaker is in a small category or with two of those, that's pretty much large bookshelf's/flour sanders. If you think bad designed half tone port cuff out counts for the lower octave or more than think again. If you think you can control that cuff either to the SPL good luck with that. EQ-APO has a equal level loudness compensation (ISO 226 2003) and plugin suport for let's say convolver and phase third part plugins to integrated PEQ. I use JRiver for better WDM driver and in generally more stable working.
In the end let me rephrase the question. Why would anyone gave up on the +6 dB boots in area of 60 Hz and under where it's a long unified wave anyhow? There is no speaker ever made that won't hugely benefit from this.
 
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